Conical-flow fan.



H. F. HAGEN.

CONICAL FLOW FAN. APPLICATION FILED 1AN.13. 19|3.

Patented Sept. 26, 1916.

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n Hom/1213 ya ya. w )M1/W H. F. HAGEN. CONICA!- FLOW FAN. APPLICATIONFILED JAN. la. 1913.

Patented Sept. 26, 1916.

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UNITED STATES PATENT OFFICE.

HAROLD F. HAGEN, OF JERSEY CITY, NEW JERSEY, ASSIGNOR T0 THE GREEN FUELECONOMIZER COMPANY, OF MATTEAWAN, NEW YORK, A CORPORATION OF NEW YORK.

CONICAL-FLOW FAN.

Application led January 13, 1913.

To all 'whom it may concern Be it known that I, HAROLD F. HAGEN, acitizen of the United States, residing at Jersey City, New Jersey, haveinvented certain new and useful Improvements in Conical-Flow Fans, ofwhich the following is a full, clear, and exact description.

The invention which constitutes the subject matter of this application,relates to a diffuser applicable to fans, compressors, pumps and otherkindred apparatus.

It is well known that the axial flow or propeller type of fan isespecially7 desirable where large quantities of air lare to be moved butonly against comparatively low pressures. It is also known that with theradial flow fan, generally called the centrifugal fan, it is extremelydifficult to Secure a large volume of air at a moderateA pressure andstill secure a high efficiency unless the fans are made of a very largesize so that the velocities of the fluid through the passages are suchas to make the velocity heads small.

Radial flow fans necessitate the turning of the air through a rightangle, and inasmuch as a large volume at moderate pressure requireslarge air passages, it is difficult to secure, mainly on account of theabove mentioned right angle turn, an even distribution of the air. As aresult radial fans designed for large volumes, work ratherinefficiently.

Any rotating impeller which imparts energy to a fluid passing throughit, must give the particles of that fluid a rotative velocity componentin the direction of the rotation of the impeller. This rotative velocitycomponent is in fact a measure of the amount of work doneby the fan.Consequently if the volume delivered is constant a fan developing a highpressure, that is doing a' large amount of work, will necessarily impartto the fluid particles a rather large rotativel velocity component; anda fan working at a low pressure, doing a small amount of work willimpart to the Huid particles a smaller rotative velocity component. In aradial fan, this component of the velocity is useful and appears, thoughsomewhat diffused, as useful velocity head at the outside of thevolute.v But in the axial fiow fan the head represented by the rotativevelocity component at the Specification of Letters Patent.

Patented Sept. 26, 1916.

serial No. 741,717.

fan outlet is entirely lost. It serves no useful purpose in moving thefluid through the passages. For this reason an axial flow fan cannotWork efficiently at other than very low pressure where this waste energyis small.

I have found in all fans as hitherto constructed that the sides v,of thewalls have not had the proper relation with respect to each othervandthe direction of the fiow of the fiuid therethrough inasmuch as thestreamrdoes not fill the space between the walls owing to the fact thatthe area of the space always increases in the direction of flow whereasthe area should remain sub'- stantially constant in order to obtain thebest results in the conversion of the rotative velocity energy intopressure energy.

The invention therefore consists in providing mechanism for convertingthis rotative velocity of the axial or propeller type fans, with theirexcellent distribution of the fluid, into higher pressures with goodefficiencies, by providing a diffuser therefor of the type described indetail below. This diffuser is employed to provide an efficient meansfor converting the rotative kinetic energy into useful potential en rgyor static pressure through the actio of the law of the constancy of themoment of momentum. This diffuser therefore may be applied to an axialfan thereby increasing its pressure range and its efficiency.

Referring to the drawings, wherein lI show the preferred embodiments ofmy invention; Figure 1 shows a construction of a fan embodying theprinciple of my invention wherein the inner and outer co-axial wallsofthe diffuser are curved concavely with respect to the axis of the fan.Fig. 2 illustrates a modified construction which is an approximation ofthe device shown in' Fig. 1. Fig. 3 shows a construction of a fanembodying the principle of my invention, the walls of which are curvedin a direction which is convex to the axis of the fan and approach eachother as theradial distance increases. Fig. 4 illustrates a modificationwhich is an approximation of the device shown in Fig.

The essential feature of my invention, as will appear from theembodiment shown, consists in the provision of a space which issubstantially free from eddies and is accomplished by employing co-axialmembers the walls of which are so inclined to the axis that theyapproach each other as the radial distance from the axis increases.

Referring specifically to Fig. l, the character A represents theinterior wall or member and the character B the exterior member which isco-axial with the member A both of which are stationarily mounted, themember B preferably secured to the suction ring C by means of boltsshown at D, and the member A is preferably secured to the member B bythe means shown at E. The suction ring is in turn preferably supportedbyasuitable base, such as shown at F. The surface of the members orwalls A and B are connected by strap-iron supports and approach eachother in the direction of fiow of the gases therethrough in the mannerabove stated. As a result of so placing the two surfaces not only is theforward velocity of the entering fluid diffused, but the circumferentialvelocity is diffused as well.

Fig. 2 shows a construction similar to the construction shown in Fig. l;but in this case the members A and B are co-axial conical members andare so arranged, as in Fig. 1, that the area between the surfaces, that1s the area these surfaces intercept on planes perpendicular to the axisof the shaft, is substantially constant, and the walls of the diffuserare inclined toward each other in the direction of the flow of fiuidtherethrough. For instance, this area at the point of entrance of thefluid between said surfaces is equal or substantially equal to this samearea at the point of exit of said Huid.

In Fig. 3 I have shown the same principles embodied in a diffuserwherein the walls A and'B are curved reversely to the curvature of thewalls shown in Fig. 1, and also approach each other as the radialdistance from the axis of the fan increases. The device is soconstructed that the sectional area at increasing radial distances issubstantially constant, or very slightly decreasing, and the formationof the path of the fluid through the fan is changed from an axial into asubstantially corneal direction.

Fig. 4 shows a form of diffuser which approxlmates the walls of theconstruction shown in Fig. 3 and for practical purposes, like theconstruction shown in Fig. 2, may be used with substantially the sameefficiency. These defining walls like those shown in Fig. 2, are alsoco-axial conical members the outer surfaces of which are inclined towardeach other in the direction of the flow of fluid therethrough.

With reference to the construction of my conical flow diff'users asshown in Figs. 1 and 3, the exact inclination of the walls is perfectlydetermined in accordance with the theory of whirl-free stream linemotion. In

my investigations, however, I have found that the limiting walls of thediffuser to be in exact accordance with thistheory will be curved,either concavely or convexly with respect `to the axis of the flow, andapproach each other as the radial distance from the axis of the fanincreases. I have also found that these walls can be curved differentlywith respect to the axis of the fan and 0f course each will be expressedby different mathematical equations or formulae. I give one of themathematical equations of my invention below:

Equation l K---Cac-Dr2 where C is a constant, the axial distance fromthe origin and D is another constant. This equation is the formula of a.parabola and is arrived at from the underlying principles of the theoryof whirl-free stream line motion. In order to avoid the prolixity ofdescription I will not enter into a discussion of the necessary steps inarriving at the conclusion, as it is thought that this will be clearlyunderstood by those skilled in this particular art. By regarding K asthe parameter and assigning to it different values the equation may beconsidered to represent a family of congruent parabolas. Using these torepresent a fluid flow, we have a mathematical expression of the actionof the fluid. Any two of the congruent parabolas may be taken as thelimiting walls of the diffuser and through this passage, defined by thelimiting walls, the fluid can flow 100 free from whirling motion. Aconstruction in accordance with this equation is illustrated in Fig. 1,in which the curves are concave toward the axis of the fan. From theunderlying principles of the whirl-free 105 theory other formulae may bedeveloped and the limiting walls of the diffuser constructed inaccordance therewith to provide a substantially conical passage throughwhich the fluid can fiow free from whirling motion.

Another mathematical equation which may be evolved from the underlyingprinciple of whirl-free stream line motion is the following:

where C is a constant, r the radial distance from the axis of the fan,and .fr the axial distance from an origin. By regarding K 120 as theparameter and assigning to it different values the equation will befound to represent another family of curves which approach each other asthe radial distance from the axis of the fan increases. In using 125these curves again to represent a Huid fiow we have a mathematicalexpression of the action of the fluid any two of which may be taken asthe limiting walls of the diffuser which walls define a passage freefrom 130 whirling motion.

A diffuser constructed in accordance with this equation is illustratedin Fig. 3 in which the curves are shown as being convex toward the axisof the fan. As in the case of the diuser illustrated in Fig. 1 otherformulae may be developed and the limiting Walls of the diffuserconstructed in accordance therewith to provide a passage through whichthe Huid can flow free from whirling motion. Of course in designing adiffuser the values assigned to the constants of these equations must beselected with due regard to the nature of the fiuids. It will beapparent, however, that in the construction shown in Fig. 3 the changeof width of the passage formed by the limiting Walls of the diffuser isgreater owing to the fact that the radial component of the velocityincreases more rapidly with respect to the axial component than is thecase with constructions made from formulae which represent lines curvedreversely from the lines illustrated in said Fig. 3.

I have also found as a matter of fact that if conical Walls, such asshown in Figs. 2 and 4, and having substantially the same degree ofinclination,be substituted for the curved walls they give a result inoperation which approximates the efficiency derived from the curvedWalls and are preferred in actual practice where diffusers manufacturedfrom sheet metal are required and in these cases the flow of fluidthrough the passage will be substantially whirl free.

It Will be very apparent from the above description that lar e changesin the velocity of the Huid Wil be effectively avoided in passingthrough the diffuser. As a result, the formation of eddies is prevented2nd the flow through the passage whirlree.

In all the embodiments herein shown an impeller with suitable blades Gis used, properly disposed upon the shaft H.

It is to be understood that I do not limit myself to the exactconstructions shown, as many changes may be made in points of detail andother embodiments resorted to without necessarily departing from thespirit and scope of the invention as defined by the appended claims.

That I claim is:

l. In combination, a rotary impeller and a diuser comprising inner andouter Walls or casings defining a substantially conical passage for theflow of' fluid therethrough, said walls so related that the areas theyintercept on the surface of cylinders coaxial With the axis of theiinpeller increases substantially in direct proportion to the radius ofsuch cylinders and also the area intercepted by said diffuser walls onplanes perpendicular to the axis of the impeller is substantially aconstant.y whereby the radial and rotational velocity components aredecreased While the axial velocity component is kept constant, and aconversion from velocity to pressure is secured and eddies are avoided.

2. In combination, a rotary impeller, and a diffuser comprising outerand inner limiting walls or casings defining a substantially conicalpassage for the flow of fluid therethrough, said walls so inclined tothe axis that they approach each other as theradius increases, andcontinue throughout their whole extent the same direction of curvaturetoward the axis as the limiting walls of the impeller with which theyare combined.

In testimony whereof I affix my slgnature in the presence of twosubscribing witnesses.

HAROLD F. HAGEN.

Witnesses:

WM. BOHLEBER,V M. LAWSON DYER.

Correction in Letters PatentNo.,1,199,37f1f.

' requiring whirling motion. A diffuser constructed in accordance Withthis equation is illustrated in Fig. 3 in which the curves are shown asbeing convex toward the axis of the fan. As in the case of the diffuserillustrated in Fig. l other formulae may be developed and the limitingWalls of the diffuser constructed in accordance therewith to provide apassage through Which the fluid can flow free from whirling motion. Ofcourse in designing a diffuser the values assigned to the constants ofthese equations must be selected with due regard to the nature of thefluids. It will be apparent, however, that in the construction shown inFig. 3 the change of width of the passage formed by the limiting wallsof thediffuser is greater owing to the fact that the radial component ofthe velocity increases more rapidly With respect to the axial componentthan is the case With constructions made from formulae which representlines curved reversely from the lines illustrated in said Fig. 3.

I have also found as a matter of fact that if conical Walls, such asshown in Figs. 2 and 4, and having substantially the same degree ofinclinatiombe substituted forthe curved walls they give a result inoperation which approximates the efficiency derived from the curvedWalls andare preferred in actual practice where diffusers manufacturedfrom sheet metal are required and in these cases the flow of fluidthrough the passage will be substantially whirl free. Y

It will be very apparent from the above description that large changesin the velocity of the fluid will be effectively avoided in passingthrough the diffuser. As a result, the formation of eddies is preventednd the flow through the passage Whirlree.

In all the embodiments herein shown an the same [SEAL] increases, and

Signed and sealed this 6th day of March, A. D., 1917.

impeller with suitable blades G is used, properly disposed upon theshaft H.

It is to be understood that I do not limit myself to the exactconstructions shown, as many changes may be made in points of detail andother embodiments resorted to without necessarily departing from thespirit and scope of the invention as defined by the appended claims.

What I claim is:

l. In combination, a rotary impeller and a diffuser comprising inner andouter walls or casings defining a substantially conical passage for theflow of fluid therethrough, said walls so related that the areas theyintercept on the surface of cylinders coaxial with the .axis of theimpeller increases substantially in direct proportion to the radius ofsuch cylinders and also the area intercepted by said diffuser walls onplanes perpendicular to the axis of the4 impeller is substantially aconstant, whereby the radial and rotational velocity components aredecreased while the axial velocity component is kept constant, and aconversion from velocity to pressure is secured and eddies are avoided.-

2. In combination, a rotary impeller, and a diffuser comprising outerand inner limiting Walls or casings defining a substantially conicalpassage for the flow of fluid therethrough, said walls so inhlined tothe axis that they approach each other as the-radius continue throughouttheir whole extent the same direction of curvature toward the axis asthelimiting walls of the impeller With which they are combined.

In testimony whereof I affix my signature in the presence of twosubscribing Witnesses.

, HAROLD F. HAGEN. Witnesses:

WM. BOHLEBER, M. LAwsoN DYER.

It is hereby certified that in Letters Patent o; 1,199,374, grantedSeptember 26, 1916, upon the application of Harold F. Hagen, of JerseyCity, New Jersey, for an improvement in Conical-Flow Fans, an errorappears inthe printed specification correction as follows: Page 1, line52, for the Word outside read outlet; and that the said Letters Patentshould be read with this correction therein that may conform to therecord of the case in the Patent Office.

a. W, ILH. LAY,

I Acting Uommissioner of Patents.

Correotion in Letters Patent No. 1,199,374.

It is hereby certified that in Letters Patent No. 1,199,374, grantedSeptember 26,

. 1916, upon the application 0f Herold F. Hagen, of Jersey City, NewJersey, for an improvement in Geniaal-Flow' Fans, an error appears inthe printed specification requiring correction as follows: Page 1, line52, for the word outsice read outlet;

and that the said Letters Patent should be read with this correctiontherein that the same muy conform to the record of the case in thePatent OHce.

Signed and Sealed this 6th day of March, A. D., 1917.

E. W. H. CLAY,

[SEAL] Ming commissioner of Panne.

